b)
\ (\frac{1}{3}-\frac{1}{2})^{-1}=(\frac{2}{6}-\frac{3}{6})^{-1}=(-\frac{1}{6})^{-1}=-6
c)
\ (\frac{1}{3}-\frac{1}{5})^{-3}:(\frac{1}{5}+\frac{1}{3})^{-3}=(\frac{5}{15}-\frac{3}{15})^{-3}:(\frac{3}{15}+\frac{5}{15})^{-3}=
\ (\frac{2}{15})^{-3}:(\frac{8}{15})^{-3}=(\frac{15}{2})^3:(\frac{15}{8})^3=\frac{15^3}{2^3}:\frac{15^3}{2^9}=\frac{15^3}{2^3}*\frac{2^9}{15^3}=
skracamy na krzyż 15^3 z 15^3 oraz 2^3 z 2^9
\ 2^6=64